Smoke extended bicubic

[raoni]

Hello there ,
Does anyone knows how to link the ext. bicubic grid to an axis , so I can use the tracking info to move this grid along with the shot ?
For exemple , to make a person smile using the ext, bicubic is simple , but if the person moves , the ext. bicubic stay still and I have no axis to perform a tracking .
If anyone have any idea , let me know .
Thanks
Raoni

[Tom]

if you don´t want to do this in the warper you have to stabilize the shot with the stabilizer, do your bicubic effect and track it back into your scene with a soft matte

hth
tom

raoni wrote:

Hello there ,
Does anyone knows how to link the ext. bicubic grid to an axis , so I can use the tracking info to move this grid along with the shot ?
For exemple , to make a person smile using the ext, bicubic is simple , but if the person moves , the ext. bicubic stay still and I have no axis to perform a tracking .
If anyone have any idea , let me know .
Thanks
Raoni

[raoni]

Thankx Tom ,
I’ve tried this way before but in a large scale production … it spends too much time . And the warper I dont have , I’m using smoke 6 on linux .
I will probably have to do this is on flame , wont I ?
Well , Tankx again .

Raoni.

[Tom]

you cuold try to stabilize the image surface and than apply the negative stabilization to a extra axis. don´t know if it works but you could give it a try in flame. no clue wether you could do this in smoke…

tom

raoni wrote:

Thankx Tom ,
I’ve tried this way before but in a large scale production … it spends too much time . And the warper I dont have , I’m using smoke 6 on linux .
I will probably have to do this is on flame , wont I ?
Well , Tankx again .

Raoni.

[raoni]

Thats a nice idea , even for smoke . I could stabilaze the front and give the layer the negative values ( just a matter of names ). I’ll try that and let you know if works.
Thankx .

Raoni

[Richard Mckeand]

Hi Guys,
This is a workaround I’ve used in Flame for xbic spline tracking:
1 – stabilise plate
2 – create front & matte sources for layer
3 – copy or link positional data to the front and mate nodes then negate

if you need to align a particular vertex to a point in your image you could use linking & then do a translate y on your source image stabilise curves for better lineup

Hope this helps

[StevieB]

Wow, this is an old thread from 2005. Here\’s a method I learned from an old NAB master class taught by Philippe Soiero. I don\’t think this method was available in 2005.

Make your extended bicubic. Add a Diffuse map to it. In this example, axis1 on ext bicubic and axis2 on diffuse map. Set up an expression for axis2 position such as, -axis1.position. The result of this is that when you move the ext bicubic x or y position, the texture will move in a negative direction keeping the picture locked and only moving the mesh.

Then composite this over the original shot.

If you need rotation and scaling, link axis2 center values to axis1 position so that the rotation occurs at the proper position.

To negate the scaling, this expression will work for axis2 scaling: 1/(axis1.scaling/100)*100

It used to be more difficult than this because textures used to scale from the lower left corner. Now they scale from the center.

The extended bicubic doesnt even have to be the same resolution as the original shot. You can use a small frame, say 200×200 for the extended bicubic if you just want to distort a small part of the shot.

If you are using the tracker, be sure to use an offset axis on the diffuse map as well as the ext. bicubic to line everything up.

I know you can also do this with source nodes but that can increase processing time. The texture mapping is fast.

Even though I have done this on Flame, it should also work on Smoke now that you have expressions which were not available in 2005.

Steve Beecher
Flame Artist
Disney ABC Television

[Author]

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